A typical arrangement for detecting the rotational speed of a rotating member such as the camshaft of a fuel injection pump involves a toothed wheel coaxially fixed to the rotating member and a suitable sensor disposed in proximity to the toothed wheel for providing a pulse upon each occurrence of tooth/sensor juxtaposition. These pulses may be converted to logic states in a digital electronic fuel control or may be converted to analog voltage levels in an analog electronic fuel control.
A typical arrangement for detecting the timing of a rotating member involves coaxially fixing a wheel having a single tooth or detent to the rotating member and a suitable sensor disposed in proximity to the wheel for providing a pulse per revolution upon the occurrence of tooth (or detent)/sensor juxtaposition.